docs: def _is_saccharide_arrow(self, before, after):
          """Return True if the arrow is in a chemical name."""
          if (before and after and before[-1].isdigit() and after[0].isdigit() and
              before.rstrip('0123456789').endswith('(') and after.lstrip('0123456789').startswith(')-')):
              return True
          else:
              return False